How does an automatic road barrier decide when a vehicle is coming?

Submitted ⁨⁨1⁩ ⁨year⁩ ago⁩ by ⁨tired_lemming@sh.itjust.works⁩ to ⁨nostupidquestions@lemmy.world⁩

So just something that’s been on my mind. At my workplace there’s an automatic road barrier that lifts up and down when vehicles arrive. However, it’s not used for l a carpark system when people wave their tickets or something. It just goes up and down when a vehicle shows up.

However, it sometimes goes up for when say a pushcart is being rolled over whereas it wouldn’t for a guy pushing a bin.

So tldr, how does an automatic road barrier decide that yes, a vehicle is coming, and therefore opens up?

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atlasraven31@lemm.ee ⁨1⁩ ⁨year⁩ ago
Same as traffic lights. “Inductive-loop traffic detectors use an electrically conducting loop embedded in the pavement to send a signal to the traffic control system to indicate the presence of a vehicle.”

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- otter@lemmy.ca ⁨1⁩ ⁨year⁩ ago
  So a large wooden horse could slip by without detection
  
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  - astraeus@programming.dev ⁨1⁩ ⁨year⁩ ago
    If the large wooden horse is full of men in metal armor, purely hypothetically speaking, would the loop still not pick up the large wooden horse?
    
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  - AmidFuror@kbin.social ⁨1⁩ ⁨year⁩ ago
    How about a wooden badger?
    
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- Narc082@aussie.zone ⁨1⁩ ⁨year⁩ ago
  This, it’s like a metal detector but, bigger. Temporary boom gates might use infrared motion sensors like automatic lights.
  
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  - TWeaK@lemm.ee ⁨1⁩ ⁨year⁩ ago
    It’s bigger in overall structure size, but isn’t really that big itself. It’s just a wire loop, they can be installed into existing roads with minimal effort - they just dig a narrow trench and then seal it up, it doesn’t require more tarmac.
    
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- tired_lemming@sh.itjust.works ⁨1⁩ ⁨year⁩ ago
  Huh, so that’s a completely new concept I’ve learned today. Time to do more reading. Thanks!
  
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  - Tomahtoes@lemmy.world ⁨1⁩ ⁨year⁩ ago
    Check the road in front of the gate. Those loops are usually installed after the asphalt so there should be a loop patched up with tar a bit smaller than a footprint of an average car.
    
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Nanomerce@lemmy.world ⁨1⁩ ⁨year⁩ ago
looks like it really depends, https://us.beasensors.com/en/segment/vehicle-sensing-solutions/barriers/ has some information about the specific sensora they use.

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- TWeaK@lemm.ee ⁨1⁩ ⁨year⁩ ago
  Your URL code is wrong. [https://us.beasensors.com/en/segment/vehicle-sensing-solutions/barriers/](url), this gives the URL as text but the link is just URL.
  
  This is working URL code: https://us.beasensors.com/en/segment/vehicle-sensing-solutions/barriers/ although you could just type the URL and the website/app should make it a link automatically.
  
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  - algorithmae@lemmy.one ⁨1⁩ ⁨year⁩ ago
    Good bot
    
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Kidplayer_666@lemm.ee ⁨1⁩ ⁨year⁩ ago
There could be a motion sensor behind maybe? It could be one of those places that have a bunch of coils on the ground, wherein a large enough mass of metal gets detected by changing magnetic or electric fields, or something else entirely

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FuglyDuck@lemmy.world ⁨1⁩ ⁨year⁩ ago
Could be a lot of ways- an IR beam some where before the barrier. A motion sensor (usually IR or IR+ultrasound). Possibly some sort of movement detection on the security cameras.

Or a magnetic loop sensor, which is my guess. (You’d see the other sensors.)

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